Problem: $ { \left[\begin{array}{rrr}{4} & {-2} & {-2} \\ {2} & {3} & {3}\end{array}\right]+\left[\begin{array}{rrr}{2} & {0} & {-2} \\ {-1} & {3} & {3}\end{array}\right] = {?} } $
Explanation: To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{rrr}{4}+{2} & {-2}+{0} & {-2}+{-2} \\ {2}+{-1} & {3}+{3} & {3}+{3}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{6} & {-2} & {-4} \\ {1} & {6} & {6}\end{array}\right]}$